TOMEI VALVE GUIDE SET For NISSAN SKYLINE RB25 RB20 163047Brand TOMEI Product Number 163047 Compatible Car NISSAN SKYLINE Compatible Engine RB25 RB20 Product Description We chose to use Phosphor Bronze (Cn Sn P alloy) to make our Valve Guides, for its highly tensile and superior heat transferring ability, which is vital in high power and high RPM outputting engines. Since race engines these days require more power at higher RPM use, these engines now experience more extreme heat conditions. These conditions